Method for producing diol

ABSTRACT

The present invention provides a method for producing a diol having a specific structure in high yields while keeping high selectivity. Provided is a method for producing a diol having a specific structure by oxidizing an olefin having a specific structure in the presence of a ruthenium compound.

TECHNICAL FIELD

The present invention relates to a method for producing a diol. The present invention also relates to a composition containing a diol.

BACKGROUND ART

Patent Literature 1 reports conversion of an olefin oxide to a 1,2-diol or a 1,2-diol ether by reacting an olefin oxide with water appropriately using an acidic catalyst or a basic catalyst.

Non-patent Literature 1 reports production of a diol by oxidizing an olefin such as methyl cinnamate using ruthenium trichloride and an acid in a solvent mixture of ethyl acetate, acetonitrile, and water.

CITATION LIST Patent Literature

-   Patent Literature 1: JP 2010-527748 T

Non-Patent Literature

-   Non-patent Literature 1: B. Plietker, M. Niggemann, “An Improved     Protocol for the RuO₄—Catalyzed Dihydroxylation of Olefins”, Org.     Lett., 2003, 3353-3356.

SUMMARY OF INVENTION Technical Problem

The present invention aims to provide a method for producing a diol having a specific structure in high yields while keeping high selectivity.

Solution to Problem

The present invention relates to a method for producing a diol, including

oxidizing an olefin represented by Formula (1):

wherein R¹ is a group having an electronegativity of 3.0 to 5.0; and R² to R⁴ are each independently a hydrogen atom, a cyano group, or an optionally substituted alkyl group, in the presence of a ruthenium compound to produce a diol represented by Formula (2):

wherein R¹ to R⁴ are as defined above (hereinafter also referred to as “the first production method of the present invention” or “the first production method”).

In the first production method of the present invention, preferably one of R² to R⁴ is a hydrogen atom.

In the first production method of the present invention, preferably two of R² to R⁴ are hydrogen atoms.

In the first production method of the present invention, preferably R² to R⁴ are all hydrogen atoms.

In the first production method of the present invention, the ruthenium compound can be collected after the oxidization of the olefin.

The present invention also relates to a method for producing a diol, including

oxidizing an olefin represented by Formula (3):

wherein R⁵ is a cyano group or an optionally substituted alkyl group; and R⁶ to R⁸ are each independently a hydrogen atom, a cyano group, or an optionally substituted alkyl group, in the presence of a ruthenium compound to produce a diol represented by Formula (4):

wherein R⁵ to R⁸ are as defined above (hereinafter also referred to as “the second production method of the present invention” or “the second production method”).

In the second production method of the present invention, preferably one of R⁶ to R⁸ is a hydrogen atom.

In the second production method of the present invention, preferably two of R⁶ to R⁸ are hydrogen atoms.

In the second production method of the present invention, preferably R⁶ to R⁸ are all hydrogen atoms.

In the second production method of the present invention, the ruthenium compound can be collected after the oxidization of the olefin.

The present invention also relates to a composition containing:

a diol represented by Formula (4):

wherein R⁵ is a cyano group or an optionally substituted alkyl group; and R⁶ to R⁸ are each independently a hydrogen atom, a cyano group, or an optionally substituted alkyl group, and

an acid compound represented by Formula (5):

R⁵—COOH

wherein R⁵ is as defined above,

the composition containing the acid compound in an amount of 1,000 to 10,000 ppm.

Advantageous Effects of Invention

The first production method of the present invention with the above-described feature enables production of diols having the specific structure in high yields while keeping high selectivity.

The second production method of the present invention with the above-described feature enables production of diols having the specific structure in high yields while keeping high selectivity.

The composition of the present invention having the above-described structure exhibits an advantageous effect; specifically, it is readily extracted in a separation operation. Thus, the composition can suitably be used for obtaining very pure target objects.

DESCRIPTION OF EMBODIMENTS

The present invention is specifically described below.

The first production method is a method for producing a diol represented by Formula (2) by oxidizing an olefin represented by Formula (1) in the presence of a ruthenium compound.

The olefin is represented by Formula (1):

wherein R¹ is a group having an electronegativity of 3.0 to 5.0; and R² to R⁴ are each independently a hydrogen atom, a cyano group, or an optionally substituted alkyl group.

The electronegativity is preferably 3.3 or higher but preferably 4.6 or lower.

The electronegativity can be determined by the method described in J. Phys. Chem., 1965, 69, 3284-3291.

R¹ is preferably a cyano group or a fluorine-containing alkyl group, more preferably a fluorine-containing alkyl group. The fluorine-containing alkyl group preferably has one to 10 carbon atom(s), more preferably one to five carbon atom(s), still more preferably one to three carbon atom(s), particularly preferably one or two carbon atom(s). R¹ is furthermore preferably at least one selected from the group consisting of —CF₃, —CN, —C₂F₅, —CH₂CF₃, —CH₂CF₃, —CH₂CF₂H, —CH₂CFH₂, —CH(CF₃)₂, and —CF(CF₃)₂.

For reference, the electronegativity of several groups is as follows.

—CF₃: 3.46

—CF₂CF₃: 3.4 —CF(CF₃)₂: 3.38

—CN: 3.84 —CH₃: 2.27

Examples of the substituent include an aryl group, an alkoxy group, a halogen atom, a cyano group, an ether group, an ester group, and an amide group, all of which may contain a heteroatom. Preferred of these is a cyano group, an aryl group, a fluorine atom, or a chlorine atom; more preferred is a cyano group or a fluorine atom; and still more preferred is a fluorine atom.

R² to R⁴ are each preferably a hydrogen atom, a cyano group, or a fluorine-containing alkyl group, more preferably a hydrogen atom or a fluorine-containing alkyl group. The fluorine-containing alkyl group preferably has one to 10 carbon atom(s), more preferably one to five carbon atom(s), still more preferably one to three carbon atom(s), particularly preferably one or two carbon atom(s).

Preferably, one of R² to R⁴ is a hydrogen atom. More preferably, two of R² to R⁴ are hydrogen atoms. Still more preferably, R² to R⁴ are all hydrogen atoms.

The diol is represented by Formula (2):

wherein R¹ to R⁴ are as defined above.

Specific examples of the diol include CF₃—CHOH—CH₂OH, CF₂H—CHOH—CH₂OH, CFH₂—CHOH—CH₂OH, CF₃CF₂—CHOH—CH₂OH, CF₂HCH₂—CHOH—CH₂OH, CFH₂CH₂—CHOH—CH₂OH, NC—CHOH—CH₂OH, CH₂OH—CHOH—CH₂CN, CF₃CH₂—CHOH—CH₂OH, and (CF₃)₂CF—CHOH—CH₂OH.

The first production method is particularly suitable for producing a diol such as CF₃—CHOH—CH₂OH, NC—CHOH—CH₂OH, CF₃CF₂—CHOH—CH₂OH, CF₃CH₂—CHOH—CH₂OH, or (CF₃)₂CF—CHOH—CH₂OH.

The second production method is a method for producing a diol represented by Formula (4) by oxidizing an olefin represented by Formula (3) in the presence of a ruthenium compound.

The olefin is represented by Formula (3):

wherein R⁵ is a cyano group or an optionally substituted alkyl group; and R⁶ to R⁸ are each independently a hydrogen atom, a cyano group, or an optionally substituted alkyl group.

R⁵ is preferably a fluorine-containing alkyl group. The fluorine-containing alkyl group preferably has not more than 10 carbon atoms, more preferably not more than five carbon atoms, still more preferably not more than three carbon atoms, furthermore preferably not more than two carbon atoms. It may have one or more carbon atoms.

R⁵ may be a linear or branched fluorine-containing alkyl group.

In particular, for production in high yields while keeping high selectivity, R⁵ is more preferably at least one selected from the group consisting of —CF₃, —CF₂H, —CFH₂, —CH₂CF₃, —CF₂CF₃, —CH(CF₃)₂, —CF(CF₃)₂, —CH₂C₂F₅, —CF₂CF₂H, —CF₂CFH₂, —CFHCF₃, —CFHCF₂H, —CFHCFH₂, —CH₂CF₂CF₃, —CH₂CF₂CF₂H, and —CF₂CF₂CF₃, still more preferably —CF₃.

Examples of the substituent include an aryl group, an alkoxy group, a halogen atom, a cyano group, an ether group, an ester group, and an amide group, all of which may contain a heteroatom. Preferred of these is a cyano group, an aryl group, a fluorine atom, or a chlorine atom; more preferred is a cyano group or a fluorine atom; still more preferred is a fluorine atom.

R⁶ to R⁸ are each preferably a hydrogen atom, a cyano group, or a fluorine-containing alkyl group, more preferably a hydrogen atom or a fluorine-containing alkyl group. The fluorine-containing alkyl group preferably has one to 10 carbon atom(s), more preferably one to five carbon atom(s), still more preferably one to three carbon atom(s), particularly preferably one or two carbon atom(s).

Preferably, one of R⁶ to R⁸ is a hydrogen atom. More preferably, two of R⁶ to R⁸ are hydrogen atoms. Still more preferably, R⁶ to R⁸ are all hydrogen atoms.

The diol is represented by Formula (4):

wherein R⁵ to R⁸ are as defined above.

Specific examples of the diol include CF₃—CHOH—CH₂OH, CF₂H—CHOH—CH₂OH, CFH₂—CHOH—CH₂OH, CF₃CF₂—CHOH—CH₂OH, CF₂HCH₂—CHOH—CH₂OH, CFH₂CH₂—CHOH—CH₂OH, NC—CHOH—CH₂OH, CH₂OH—CHOH—CH₂CN, CF₃CH₂—CHOH—CH₂OH, (CF₃)₂CF—CHOH—CH₂OH, CF₃—CHOH—CH(OH) CF₃, and CF₃—CHOH—CH(OH) CH₃.

The second production method is particularly suitable for producing a diol such as CF₃—CHOH—CH₂OH, CF₃CF₂—CHOH—CH₂OH, CF₃CH₂—CHOH—CH₂OH, (CF₃)₂CF—CHOH—CH₂OH, CF₃—CHOH—CH(OH)CF₃, or CF₃—CHOH—CH(OH)CH₃.

Ruthenium compounds are potent oxidizing agents known to oxidize alkenes to ketones or carboxylic acids. They are also known to oxidize diols to carboxylic acids. It is thus a common belief that ruthenium trichloride should not be used in the production of diols while seeking high selectivity. The present inventors intensively studied methods for producing diols having specific structures. As a result, they have found, contrary to expectations, that oxidization of specific olefins using ruthenium compounds can suppress oxidization to ketones or carboxylic acids, whereby diols can be produced in high yields. Based on the finding, the present invention was completed.

Examples of the ruthenium compound include bis(cyclopentadienyl)ruthenium(0), bis(ethylcyclopentadienyl)ruthenium(II), carbonylchlorohydridotris(triphenylphosphine)ruthenium(II), carbonyl(dihydrido)tris(triphenylphosphine)ruthenium(II), chloro(1,5-cyclooctadiene)(pentamethylcyclopentadienyl)ruthenium(II), chloro(cyclopentadienyl)bis(triphenylphosphine)ruthenium(II), dichloro(benzene)ruthenium(II) dimer, dichloro(p-cymene)ruthenium(II) dimer, dichloro(p-cymene)tricyclohexyl phosphine ruthenium(II), dichloro(carbonyl bis(triphenylphosphine)ruthenium(II), dichlorotris(triphenylphosphine)ruthenium(II), ruthenium(III) acetylacetonate, ruthenium(III) chloride, ruthenium(III) iodide, ruthenium(II) oxide, and ruthenium(IV) oxide. Ruthenium(III) chloride, ruthenium(II) oxide, and ruthenium (IV) oxide are preferred, and ruthenium(III) chloride is more preferred.

The amount of the ruthenium compound may be any appropriate amount causing conversion to the diol; for example, usually 0.00001 to 2.0 mol, preferably 0.0001 to 1 mol, still more preferably 0.001 to 0.1 mol per mol of the olefin.

The oxidization is performed at preferably −50° C. to 50° C., more preferably −40° C. to 40° C., still more preferably −30° C. to 30° C., particularly preferably −20° C. to 20° C., most preferably −10° C. to 10° C.

The duration of the oxidization is not particularly limited, but is usually 0.1 to 120 minutes, preferably 1 to 20 minutes.

Changes may occur in the valence of the ruthenium in the ruthenium compound during the reaction. In the case where the ruthenium is reduced by oxidization of the olefin so that the oxidization valence of the ruthenium is reduced, the oxidization valence of the ruthenium in the ruthenium compound can be returned to the original valence by use of an oxidizing agent capable of oxidizing the ruthenium compound or by electrolysis of the ruthenium compound. The amount of the ruthenium compound to be used can be reduced by returning the oxidization valence of the ruthenium to the original valence.

In order to reduce the amount of the ruthenium compound, another oxidizing agent which is different from the ruthenium compound may be used in the diol-producing process. Any oxidizing agent other than the ruthenium compound may be used, and examples thereof include oxidizing agents (reoxidizing agents) capable of oxidizing the ruthenium compound and oxidizing agents capable of oxidizing the olefin.

In the case of using the oxidizing agent which is different from the ruthenium compound, the amount of the ruthenium compound is preferably 0.0001 to 1 mol, more preferably 0.001 to 0.1 mol.

In the case of not using the oxidizing agent which is different from the ruthenium compound, the amount of the ruthenium compound is preferably more than 1 mol but not more than 2 mol.

Preferred examples of the oxidizing agent which is different from the ruthenium compound include salts of perhalogen acids, salts of halogen acids, salts of halous acids, salts of hypohalous acids, hydrogen peroxide, ozone, salts of permanganic acid, salts of chromic acids, and salts of dichromic acids. More preferred are salts of perhalogen acids, for example, salts of periodic acids such as sodium periodate and potassium (meta)periodate. Also preferred are salts of hypohalous acids such as sodium hypochlorite.

The amount of the oxidizing agent which is different from the ruthenium compound may be any appropriate amount causing conversion to the diol; for example, usually, 0.1 to 5.0 mol, preferably 0.5 to 2.0 mol, more preferably 1.0 to 1.5 mol per mol of the olefin. Too small an amount of the oxidizing agent may slow down the conversion to the diol. Too large an amount of the oxidizing agent may promote oxidative cleavage, whereby the yield of the diol may tend to be reduced.

Preferably, the oxidization proceeds in a reaction solvent. Examples of the reaction solvent include water and organic solvents which are not affected by the oxidization.

Examples of the organic solvent include tetrahydrofuran (THF), diethylether, dichloromethane, dichloroethane, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, dimethylimidazolidinone, dimethylsulfoxide (DMSO), chloroform, carbon tetrachloride, acetonitrile, propionitrile, adiponitrile, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, and butyl propionate. Preferred of these are THF, dichloromethane, carbon tetrachloride, acetonitrile, and ethyl acetate.

In the case of using a reaction solvent, the amount thereof is usually within the range of 0.01 to 10 times, preferably 0.1 to 2 times the weight of the olefin.

Water is preferably used as a reaction solvent for the oxidization. Namely, in preferred embodiments of the first and second production methods, the olefin is oxidized in the presence of water and a ruthenium compound.

The reaction solvent may include a water-soluble solvent as well as water. The volume ratio of water and a water-soluble solvent is preferably 10:90 to 90:10, more preferably 20:80 to 80:20, still more preferably 30:70 to 70:30.

The reaction solvent may include a hydrophobic solvent as well as water. The volume ratio of water and a hydrophobic solvent is preferably 10:90 to 90:10, more preferably 20:80 to 80:20, still more preferably 30:70 to 70:30.

Preferably, the oxidization proceeds in a two-phase reaction solvent consisting of an aqueous phase and an oil phase (e.g. the above organic solvent). The reaction will be facilitated when performed in a two-phase reaction solvent. The volume ratio of the aqueous phase and the oil phase is preferably 1:1000 to 1000:1, more preferably 1:500 to 500:1, still more preferably 1:100 to 100:1, furthermore preferably 1:50 to 50:1, particularly preferably 1:10 to 10:1, although not particularly limited thereto.

In the oxidization in a two-phase system consisting of an aqueous phase and an oil phase (e.g. the above organic solvent), phase-transfer catalysts may be used. Examples include crown ethers such as 18-crown-6, 15-crown-5, and 12-crown-4, and quaternary ammonium salts such as tetrabutylammonium fluoride, tetrabutylammonium chloride, tetrabutylammonium bromide, and tetrabutylammonium iodide.

For higher selectivity, the oxidization may be performed in the presence of an acid. Examples of the acid include acetic acid, trifluoroacetic acid, sulfuric acid, hydrochloric acid, methanesulfonic acid, p-toluene sulfonic acid, and nitric acid. Two or more of these acids may be used in admixture. In particular, sulfuric acid is preferred, and it may be concentrated sulfuric acid.

The first and second production methods each may further include distillation of the diol produced by the oxidization.

In the first and second production methods, the ruthenium compound may be collected after the oxidization of the olefin. The collected ruthenium compound can be reused for oxidization of the olefin. For example, the collection can be performed by separating the ruthenium compound from the diol by any technique, subjecting a composition containing the ruthenium compound and the optionally added reaction solvent to filtration to collect the ruthenium compound as filtrate, followed by washing and drying as needed, and activating the ruthenium compound.

The composition of the present invention includes:

a diol represented by Formula (4):

wherein R⁵ is a cyano group or an optionally substituted alkyl group; and R⁶ to R⁸ are each independently a hydrogen atom, a cyano group, or an optionally substituted alkyl group, and

an acid compound represented by Formula (5):

R⁵—COOH

wherein R⁵ is as defined above,

the composition containing the acid compound in an amount of 1,000 to 10,000 ppm.

R⁵ to R⁸ are as described above concerning the second production method.

In the composition, the proportion of the diol represented by Formula (4) is preferably 30 to 99.99% by mass, more preferably 50 to 99.95% by mass, still more preferably 80 to 99.9% by mass.

The amount of the acid compound is preferably 2,000 ppm or more.

The amount of the acid compound can be measured by ¹⁹F-NMR or ¹H-NMR.

EXAMPLES

The present invention will be specifically described below with reference to, but not limited to, examples.

Example 1

Sodium periodate (22.5 g, 105 mmol) and water (30 mL) were stirred at 0° C. to 5° C., and ruthenium(III) chloride (71.5 mg, 0.35 mmol), ethyl acetate (100 mL), and acetonitrile (100 mL) were added thereto while keeping the temperature. Thereafter, 3,3,3-trifluoropropene (6.7 g, 70 mmol) was further added, followed by stirring for 5 to 10 minutes. The mixture was subjected to separation and distillation, thereby giving a composition containing CF₃—CHOH—CH₂OH and trifluoroacetic acid with a conversion rate of 98.3%, selectivity of 80.3%, and yield of 78.9%. The total trifluoroacetic acid content of the composition was 2,500 ppm.

Example 2

Sodium periodate (22.5 g, 105 mmol) and water (30 mL) were stirred at 0° C. to 5° C., and ruthenium(III) chloride (71.5 mg, 0.35 mmol), ethyl acetate (100 mL), and acetonitrile (100 mL) were added thereto while keeping the temperature. Thereafter, concentrated sulfuric acid (1.4 g, 14 mmol) was added, and 3,3,3-trifluoropropene (6.7 g, 70 mmol) was further added, followed by stirring for 5 to 10 minutes. The mixture was subjected to separation and distillation, thereby giving a composition containing CF₃—CHOH—CH₂OH and trifluoroacetic acid with a conversion rate of 97.2%, selectivity of 97.8%, and yield of 95.1%. The total trifluoroacetic acid content of the composition was 1,700 ppm.

Example 3

Sodium periodate (22.5 g, 105 mmol) and water (30 mL) were stirred at 0° C. to 5° C., and ruthenium(III) chloride (71.5 mg, 0.35 mmol), ethyl acetate (100 mL), and acetonitrile (100 mL) were added thereto while keeping the temperature. Thereafter, acrylonitrile (3.7 g, 70 mmol) was further added, followed by stirring for 5 to 10 minutes. The mixture was subjected to separation and distillation, thereby giving a composition containing NC—CHOH—CH₂OH and cyanoformic acid with a conversion rate of 97.6%, selectivity of 82.3%, and yield of 80.3%. The total cyanoformic acid content of the composition was 3,500 ppm.

Comparative Example 1

Potassium ferricyanide (155 mmol), water (120 mL), t-butyl alcohol (120 mL), and potassium osmate dihydrate (261 mg, 0.71 mmol) were stirred at 0° C. to 5° C., and 3,3,3-trifluoropropene (6.7 g, 70 mmol) was added thereto, followed by stirring for about 17 hours. The mixture was subjected to extraction and distillation, thereby giving a composition containing CF₃—CHOH—CH₂OH and trifluoroacetic acid with a conversion rate of 40.2%, selectivity of 88.4%, and yield of 35.5%. The total trifluoroacetic acid content of the composition was 500 ppm.

The conversion rate in Examples 1 and 2 and Comparative Example 1 refers to the conversion rate of an olefin (for example, 3,3,3-trifluoropropene in Example 1) measured by ¹⁹F-NMR. The selectivity was measured by ¹⁹F-NMR. The product of the conversion rate and the selectivity was considered as the yield. Table 1 shows the results.

The conversion rate in Example 3 refers to the conversion rate of acrylonitrile measured by ¹H-NMR. The selectivity was measured by ¹H-NMR. The product of the conversion rate and the selectivity was considered as the yield. Table 2 shows the results.

TABLE 1 ¹⁹F-NMR area % (standard substance: C₆F₆, solvent: CDCl₃) C═C COOH CHOH—CH₂OH Yield % Chemical shift −67 ppm −75 ppm −84 ppm Example 1 1.7 0.25 86.7 78.9 Example 2 2.2 0.17 95.1 95.1 Comparative 67.8 0.05 32.3 35.5 Example 1

TABLE 2 ¹H-NMR area % (standard substance: tetramethylsilane, solvent: CDCl₃, D₂O) C═C COOH CHOH—CH₂OH Yield % Chemical shift 5.56, 11 to 4.65, 6.01 ppm 12 ppm 3.76 ppm Example 3 1.8 0.35 96.2 80.3 

1. A method for producing a diol, comprising oxidizing an olefin represented by Formula (1):

wherein R¹ is a group having an electronegativity of 3.0 to 5.0; and R² to R⁴ are each independently a hydrogen atom, a cyano group, or an optionally substituted alkyl group, in the presence of a ruthenium compound to produce a diol represented by Formula (2):

wherein R¹ to R⁴ are as defined above.
 2. The production method according to claim 1, wherein one of R² to R⁴ is a hydrogen atom.
 3. The production method according to claim 1, wherein two of R² to R⁴ are hydrogen atoms.
 4. The production method according to claim 1, wherein R² to R⁴ are all hydrogen atoms.
 5. The production method according to claim 1, further comprising collecting the ruthenium compound after the oxidization of the olefin.
 6. A method for producing a diol, comprising oxidizing an olefin represented by Formula (3):

wherein R⁵ is a cyano group or an optionally substituted alkyl group; and R⁶ to R⁸ are each independently a hydrogen atom, a cyano group, or an optionally substituted alkyl group, in the presence of a ruthenium compound to produce a diol represented by Formula (4):

wherein R⁵ to R⁸ are as defined above.
 7. The production method according to claim 6, wherein one of R⁶ to R⁸ is a hydrogen atom.
 8. The production method according to claim 6, wherein two of R⁶ to R⁸ are hydrogen atoms.
 9. The production method according to claim 6, wherein R⁶ to R⁸ are all hydrogen atoms.
 10. The production method according to claim 6, further comprising collecting the ruthenium compound after the oxidization of the olefin.
 11. A composition comprising: a diol represented by Formula (4):

wherein R⁵ is a cyano group or an optionally substituted alkyl group; and R⁶ to R⁸ are each independently a hydrogen atom, a cyano group, or an optionally substituted alkyl group, and an acid compound represented by Formula (5): R⁵—COOH wherein R⁵ is as defined above, the composition containing the acid compound in an amount of 1,000 to 10,000 ppm. 